I am seriously considering purchasing a buffalo II dac, but if I do, I don't want to leave out anything.
First off I should say I am intending on using the I2S connection.

Basically I am looking at to two buffalo dac's and two legato boards.
What is the maximum number of placid regulators that can be used with these boards.
I read somewhere in one of the manuals that you can use between 1 and 3 regulators per dac board. Any further info about that would be appreciated.

I will probably be putting the raw supply in a separate case and the shunt regulators in the second case with the dac's and legato boards.

What would you guys purchase and how would you connect it all together to make the most extreme buffalo with stock parts.
At this point in time I am not interested in doing mods unless they have been recommended by Russ.
Later when I am familiar with the stock sound I will consider modding.

You can only use one Placid for the DAC board. You can however add 3 Trident regulators to each board. For the Legato, you can add 3 BP Placids. But somehow I doubt it'll give you much improvement over just one.

The Trident regulators can be ordered starting today. They've not yet been shipped. I just ordered 2 sets for my dual mono DAC, so I'll propably be one of the first doing dual mono with a full regulator set.

One could add a third Placid & 9V R-Core to fully separate the I/O modules like the Mux & Toslink from either channel, but this really is already pretty over the top as it is. The performance is really very good though: it simply amazes listeners a DAC can make such a difference.

The only other thing I would ask about, is what are the benefits of using r-cored transformers over toroidal?

Compared to EI/Torroid:
- Lower profile and smaller size (IMO mainly when compared to EI, Torroid is often smaller due to the higher core utilisation).
- Lower stray EM field from the round cross-sectional area and the balanced windings on either side.
- Lower core losses from no cuts the in core and minimized distance between the core and the windings. (again mainly compared to the EI)
- Lower temperature rise and noise from the round cross-sectional area and tappered slitting.

For me, the cost of getting them along the rest of the kit from the US was higher than getting shielded R-Cores shipped from France. Of course a nice shielded & potted torroid is also a good idea, but compared to those the shielded R-Core is much cheaper.